Download and install Wine for Mac. When you download it you will see that you have two applications to install, Wine and Winebottler. You have to install both of them.Wine will create a folder(called prefix) on our home/Wine Files with all the software required to run windows applications(drive C, libraries, etc.) on our mac and will install and run Metatrader 4 in this folder.WineBottler will help us to convert this folder (prefix) with metatrader into 1 package that we can run.

2. Open metatrader.exe. You will see this windows:

You can choose between running it in the default prefix or create a package with WineBottler.

We select the first option to install metatrader.

3. Install Metatrader.

4. Run Metatrader. If everything went fine now you can go to home/WineFiles/drive_c/Program Files/Metatrader
and run Terminal.exe.
You will see again the same windows asking you what to do. You have to select run directly.
If you want to make a shortcut of Metatrader you can create and alias and move it to your
desktop or dock bar.
Everytime you run Terminal.exe you are going to see the wine window first, if you want to skip
it you have to click the box dont show it again or create a bottle (which is very easy). I explain
how to do it here